Fork structure for motorcycles or the like



1949. H. A. HUTCHINS 2,477,748

FORK STRUCTURE FOR MOTORCYCLES OR THE LIKE Filed Feb. 10, 1945 /NVEN 7'0/? Hugh A/Jafckms A TTORNEY Patented Aug. 2, 1949 FORK STRUCTURE FOR MOTORCYCLES OR THE LIKE Hugh A. Hutchins, Arcadia, Calif.

Application February 10, 1945, Serial No. 577,211

6 Claims.

This invention relates to fork structures of vehicles such as motorcycles and bicycles, and has for an object to provide compact, simple and durable means for efficiently absorbing road and other shocks transmitted from the front wheel of such vehicles.

Another object of the invention is to provide means, in the steering head of a vehicle such as a motorcycle or a bicycle, for guiding the wheelcarrying stem means thereof so as to support the same in an efficient and frictionless manner.

Another object of this invention is to provide a; fork structure of the indicated type in which lateral, frictionless support of the wheel-carrying stem means thereof is afforded.

Another object of the invention is to provide a fork structure of a vehicle having means whereby the wheel-carrying stem thereof may be longitudinally adjusted in accordance with variable loading on the vehicle.

A further object of the invention is to provide a fork structure of the indicated type of vehicle contemplatin free and easy longitudinal movement of the wheel-carrying stem in the frame of said vehicle.

The various objects and features of my invention will be fully understood from the following detailed description of typical preferred forms and applications of the invention, throughout which description reference is made to the accompanying drawings, in which:

Fig. 1 is a side elevational view, in somewhat diagrammatic form, of a vehicle incorporating features of the invention.

Fig. 2 is an enlarged, longitudinal sectional view of the fork structure of the Vehicle shown in Fig. 1.

Fig. 3 is a cross sectional view as taken on the line 3--3 of Fig. 2.

Fig. 4 is a fragmentary longitudinal sectional view as taken on the line 4-4 of Fi 2.

Fig. 5 is a cross sectional view as taken on the line 5-5 of Fig. 2. i

Fig. 6 is a fragmentary view, similar to Fig. 2, and showing a modification of the invention.

The structure of the invention as herein illustrated may be said to comprise a frame l0, mounting a rear wheel H, and including a front steering fork structure l2, carrying a front wheel l3.

The frame may be formed in any conventional manner and may be so arranged as to support a rider as on a motorcycle or bicycle.

According to the invention, the means 12 may include two tubular structures 15 arranged on either side of the wheel l3. Said tubular structures l5 may each include a tube I8 and may be adjustably mounted on the frame H]. For this purpose one end, preferably the upper end, of each tube l8 may have slidable engagement in a plate [9 Which may be carried as by a king bolt or pin 16 disposed within a tube I7 forming the front end part of the frame II]. The other end of each of said tubes It may be disposed as in a sleeve 19 which may be fixed at an intermediate point of its length to a plate [9 which is similar to the plate IS. The plates l9 and l9 are preferably positioned at either end of the tube ll and said king bolt I6 passes through aligned holes in said plates to provide a pivotal mountmg for the means l2. Each sleeve I9 may have sliding engagement with its respective tube l8, and said tubes may be adjustably secured in said sleeves as by means of a clamping bolt l9. Clamping of said sleeves [9 may be achieved as by means of a. longitudinal slot it formed in each sleeve If! to provide said sleeves with clamping resiliency. By the adjustment above described, the fork structure l2 may be positioned in such relation to the frame In of the vehicle as to afford the desired cushioning effect of the shock absorbing means hereinafter described. Such adjustment may be made in accordance with the loading of said vehicle as can be understood.

The tube H! of each structure i5 is made of sufficient length and size to afford room for any of the movements which the fork may make when the vehicle is in use. Internally and longitudinally arranged within said tube I 8 and movable telescopically therein, there may be provided a wheel-carrying assembly stem structure 2| havin an end fitting M for receiving the axle or shaft of the wheel I3. Inasmuch as there are two of the structures I5 said wheel is disposed between the members 2i thereof.

Each stem structure 2| may comprise a tube 22 loosely fitted for longitudinal movement in the tube 18 and provided at one end with a cap 23. Intermediate spaced portions of the stem structure 2l may have carried therein transverse pins 24 in spaced relation, and on said pins there may be mounted rollers 25 preferably having their peripheral surfaces curved to suit the transverse curvature of the outer tube l8 against which they bear, said rollers 25 being larger in diameter than the diameter of the tube 22 for this purpose. In order to seal off the inner portion of the tube 22 from dust, and the like, the rollers 25 may be mounted in housing inserts 26 and said wheels mounted in passages 21 formed in both said inserts and in the tube 22.

3 The closure cap 23 may form part of one of said inserts 26.

The tube 8 of each of the structures I5 may be preferably capped as by means '28 at the upper end of the tube l8, and said cap 28 and the inner telescoping stem structure 2| may serve as opposed abutments for cushioning or shock absorbing meanssuch as the coil spring 29. It will benoted that the spring 29 is of considerable length so as to render it soft in action, andthat the rollers 25 are sufiiciently spaced apart to afford good and firm lateral support of the telescoping structure 2| within theltfibe f 8. {It will also be seen that rotation of the stem structure 2| within the tube I8 is obviatedby the interconnection of the tube structure 2| by'the'shaft or axle of the wheel I 3. t

The caps 28 of the structures I5 may serveto carry means wherebythe forked structure i2, and consequently thawheel l3, may be steered. iSuchfmeans may comprisehandle bars 20 which jnayf be fixeddn position as by engagement in a jthreade-d'portion 2'8 'of each cap 28. It'is-apjp'a'rent that steering movement of the fork strucigure fl is ab out the'pivot formed by the king bolt "Hi.

":Ihejassemblystructure i5 may be provided ceunteractirig'or snubber means such as -a I 3llengagedbetween' an abutment head 3| "ed by a rod 32 forming a longitudinal exl't nsj' nof 'the assembly structure 2|, and the {e wall 3 3 of "a" tubeM-di'sposed within the convolutionsf'oflthe spring '29 and suitably secured :tqthe gap "128. It'may be seen from this strucitureQthatQthespring SO may be of any suitable fjlength, not-being limited'in itslength'by the jsp'nn 2 9 *"i n'a'smuhas it 'is "disposed "Within the "cdnvo'iutiens'ef the latter spring. lThis arrangein? the fspiings 29 "arid- 30 a-fiords the prementioned soft" action of --the "long shock absorbingspring" 29. V

In i the structure of the modification shown n' Tig. GQthe asSembIy TS may-include' a1ongiudinal outer tube P8 arid in this instanceIhiay be provide'd with means for supporting 'fian'king lateral rollers having roller} engagement on eitrie defef the *inner telescoping tube ag r Inbly 2 I and V housewwithin portions 41 -the t-ube 'l'fl These rollers 10 are i'eferably-"disposed atthe lowereiid of the structiire;tithe iipper'e'ndcarryiiig a ol-ler'" 'iriilalr :to the 'rollers des'cribe d' for the earlier form of invention. FIn 5 other respects th'ef structure Fig. 7-"iiiay fo l-loufi thatof Figs' 2 17d 6; inclusive. ream the f foregoing it may be"seen*that road or ther shoks which be trarisinittedf from wheel i3 are amply absorbed by the *sp'ring hreans' ze andthat' the longitudinalincrement-er the assembl 2| or 2| which;telescopically moves *in' -tne euter' tfibe T8 or IB is'r'endered smooth alnd substantially friction-l 'ss by the -"rol-ler means 2'51a'1rd7or 40. It may a'lsobef 's'een that any rerees terrdingto ca'use "lateral -='displ-a'c'eirfent {of theftribe assenibly 2| 'in theftube lB ar F ted'fby theirrientionetl rollers 25 and"I9 so 'as t a fi'orcl-a free;an'd easy movement r the -as'- Sifibly"? ifin tl-le manner above" set f o'ith.

"IIaurin g descifibed "only certain ty pic'al, pr'ererre'd forms and applications or my 1. nvention, 9

' 70 itubestox carry'thewheel; compressionsprihgsconl do not "wish to "be i limited or 'restricte'd" to "the specific detailshere'in Stffolfh but wishfto reservef-t-o 'inyself ja'ny variations 9 or modific'ati'oris that 'm-ay"'appear to those sinned therein and ran Within the cope of the {foll6wirig' c1aiins Ha-ving des'crib'ed iriy inveritionj l claim:

spade-a "counteri 1. In a fork structure for vehicles of the character indicated, a straight elongate outer tube having pivotal engagement with the frame of said vehicle whereby said vehicle may be steered 5 and being closed at its upper end, a wheel, a straight elongate stem structure carrying said wheel and telescopicall arranged in said outer tube and depending from the lower end thereof, "means for absorbing fsli'ock transmitted by said 10 wheerth'reugh s'aid stein structiire to said outer tube, said shock absorbing means comprising spring means arranged in the outer tube and ieennn-eu "between the upper end of said stem striicture and the closed upper end of said outer 5 tube, and including a shock absorbing counter- Ia'cti'n'g snubbing spring within the outer tube "above 'the'u'pper-end of the stem, and anti-friction, means carried by the stem structure and having rolling engagement with the inner wall of said outer tube. i V

'ZRI'n -coh1bina-tion a vehicle frame of the 'eharater dscribed having =-a front end part, a wheel, a sume-tare carrying the wheel and ivetally supportedb'y sa'idfframe part-including par'anei "straight 1 tubes arranged parallel with said frame part immediately forward thereflfhlarisfi'connecting the upper-and lower end poitions 'of the tubes 'tog'et'her and to the said frame pa'rtfstr'aight stems carried i by the tubes 3 to reciprocate-therein and projecting downwardly frciih the -tubes to carry the "wheel, compress'io'n 's'pring's confii'i'ed" in the upper end portions he tubes ab'eve the upper ends of the stems, Rand r'riea'ns 'c'u-shiohing downward movement of the stems in the tubes including heads in'the apper portions 0f the tubes c'onnected to the upper ends ofithe-stems 'and compression springs supporting 'the heads and located Within the first'mientioned cempressidn springs above the 4 upper ends of the stems.

3 lnicombin'a'tion'a vehicle frameof the character' describdhaving a front end part, a wheel, an'd a -sti"ucture'=(:arryingthe wheel and pivotallyb'supported :by said "frame =part including 5 spaced parallel straight tubes arranged-parallel with said' frameipart' immediately forward there- ;of, :means connecting the 1 upper and lower end zport-ions': of' th'e tubes to'gether "and to the said i fram'e part, fsti'aight stems -entering the tubes no from -'-thi'ri1lower endsand *carrie'dby the tubes to reciprocate thereinand projecting downwardly from the tubes to man 4 the wheel, compresi sien' springs confined in' the upper end 1 portions of the tubes above the upper entis of'the stems, "st and means cmifind within the compression =s'prmgs and above the 'uppersends of *theste'ms cushioning downward movement of the stems in thetub-es. I 4. In combination a vehicle "frame or the *i fl eharacter describedwaving a front end part, a wheel, and a strueturecarrying thewheelfland i-pivotall'y' supported 'by' said :frame part on a single pivotal axis including =spa'ced parallel Fstmlight tubes arranged! parallel with said frame part immediately 'forward thereof, means connecting the upper' and lower end t-portions of' the ---tub'es together and to 'the s'aid 'frame part, --straight" 'stems"carried b ithe tubes to recipro- 'cate th'erein ahd proj'e'cting'downwardly from the rs-1 :initheauuesirrem their upper'ends a-ndterminating above the upper ends of the stems, heads in the tubular members and connected to the stems, and compression springs carried by the tubular members to support the heads.

5. In combination a Vehicle frame of the character described having a front end part, a wheel, and a structure carrying the wheel and pivotally supported by said frame part on a single pivotal axis including spaced parallel straight tubes arranged parallel with said frame part immediately forward thereof, means connecting the upper and lower end portions of the tubes together and to the said frame part, straight stems carried by the tubes to reciprocate therein and projecting downwardly from the tubes to carry the wheel, compression springs confined in the upper end portions of the tubes above the upper ends of the stems, and means cushioning downward movement of the stems in the tubes including tubular members extending downwardly in the tubes from their upper ends and terminating above the upper ends of the stems, rods projecting up from the stems into the tubular members, heads on the rods in the tubular members, and compression springs supported by the lower end portions of the tubular members and engaged under the heads.

6. In a structure of the character described a straight tube, a straight stem mounted to reciprocate in the tube and terminating therein,

and cushioning means in the tube confined between the upper end thereof and the inner end of the stem including, an outer compression spring acting to check inward movement of the stem in the tube and an inner compression spring within the outer spring acting to check outward movement of the stem, the inner spring being supported by a sleeve extending into the outer spring from the upper end thereof.

HUGH A. HUTCHINS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

